Just as expected from a Birkeland current touching down, the central peak rotates one way, you can see the between darker layer (no white, rotating the other way) and then the larger patch.

Dotini wrote:
Something funny has happened. The two big bright spots in the upper right formation have gone missing.

The light dissappeared because you cant resolve a discharge in finer detail when you get closer to the surface, the surface only has touchdown points, the 'bright' can only be seen from a larger distance (ie light spreads). The closer you get the less bright it will be.

Steve Smith wrote:An electric discharge from what?

Steve

Wrong question, an electric discharge just is. Where electrons and ions recombine, where electrons/ions are stripped from surface material (aka sputtering).

It is impact by solar wind.

You can also see the crater is not completely flat bottomed yet, this could still happen (remember it is rotating).

Just as expected from a Birkeland current touching down, the central peak rotates one way, you can see the between darker layer (no white, rotating the other way) and then the larger patch.

Dotini wrote:
Something funny has happened. The two big bright spots in the upper right formation have gone missing.

The light dissappeared because you cant resolve a discharge in finer detail when you get closer to the surface, the surface only has touchdown points, the 'bright' can only be seen from a larger distance (ie light spreads). The closer you get the less bright it will be.

Steve Smith wrote:
An electric discharge from what?

Steve

Wrong question, an electric discharge just is. Where electrons and ions recombine, where electrons/ions are stripped from surface material (aka sputtering).

It is impact by solar wind.

Average values for the solar wind's velocity, density, and magnetic field strength at the orbit of the Earth: 468 km per second; density 8.7 protons per cubic centimeter, and 6.6 nT, respectively. Since there is a 27-fold dilution of the solar wind at Jupiter, one assumes a significant reduction in strength at the orbit of Ceres.

I submit that the solar wind is so diffuse that there's no possibility that a Birkeland current with sufficient strength is eroding Ceres. No "sputtering" is taking place. Even as close as Earth orbit, the solar wind doesn't erode craters in the north or south polar regions, where it reaches the ground. Whatever happened to Ceres probably occurred thousands of years ago. Ceres and Vesta are vacuum sealed mausoleums.

A surprising bonus observation came from Dawn's gamma ray and neutron spectrometer. The instrument detected three bursts of energetic electrons that may result from the interaction between Ceres and radiation from the sun. The observation isn't yet fully understood, but may be important in forming a complete picture of Ceres.

The irregular shapes of craters on Ceres are especially interesting, resembling craters we see on Saturn's icy moon Rhea," said Carol Raymond, Dawn's deputy principal investigator based at NASA's Jet Propulsion Laboratory, Pasadena, California. "They are very different from the bowl-shaped craters on Vesta."

Images of the poles of Ceres would seem to show more 'action' having occurred there. http://dawn.jpl.nasa.gov/carousel/PIA20126_labeled.jpg
Our moon also seems to show a higher crater density and an overall chewed-up appearance, but the astronomy sites assured me this was just an illusion, crater density was no greater at the poles. I'd have to say that there has been a far greater amount of electrical activity at the poles, and that the cratering is electrical, which much raise the question as to if all cratering on all planets, moons, asteroids is electrical in nature and not from impacts. Why would the poles be more attractive to impactors?

In order to change an existing paradigm you do not struggle to try and change the problematic model. You create a new model and make the old one obsolete. -Buckminster Fuller

Nothing is "vacuum sealed" in the Solar system.
There is too much plasma, or wind, to call it a true vacuum, and that wind connects every body to the Sun.

Any discharge comes from an highly charged area and goes to a relatively less charged area.
Sometime it is said, from a positively charged area to a negatively charged area.
More readily visible on the Sun, when you look at [photos of] sunspots, which are just greatly more active versions of what we observe happening in this crater, that is puzzling everybody.

Any body that is receiving a charge, will develop some regions which are more charged than others, and then currents form at the surface to discharge the higher charged regions.

And all the bodies in the Solar system are receiving charge from the Sun.

There's nothing happening in Occator crater. The salt deposits were created long ago. If you want to think of zero atoms as a "true vacuum" then you're not thinking about how the word is applied. University Corporation for Atmospheric Research (UCAR): solar wind density near Earth is only 6 atoms per cubic centimeter. One suspects that there are fewer around Ceres. CERN holds the record for the lowest pressure attained on Earth, 1000 atoms per cubic centimeter (<1×10^-13 torr).

The solar wind is so tenuous it is a thousand times less dense than a puff of smoke, so interactions with the solar wind are not expected at Ceres. What is detected are cosmic ray impacts. Since there is no atmosphere to intercept them, they strike the surface regolith directly. Those cosmic ray impacts create the gamma-rays and neutrons that Dawn's GRAND instrument sees.

From an interview with Dawn Mission's Principal Investigator Christopher Russell, Ph.D., Professor of Geophysics and Space Physics, University of California-Los Angeles on September 1, 2015.

SO, BRAND NEW INFRARED SPECTROMETER DATA FROM OVER THE BRIGHT SPOTS INDICATES THAT THEY ARE NOT H2O WATER ICE, BUT SOMETHING ELSE. AND THAT TIES TO A QUESTION ABOUT HAZE. NATURE REPORTED AFTER YOUR JULY 21ST MEETING AT NASA-AMES RESEARCH CENTER IN MOFFETT FIELD THAT “HAZE COVERS ABOUT HALF OF THE CRATER AND STOPS AT THE RIM.” WHAT COULD POSSIBLY COME ONLY HALF WAY IN THE CRATER AND STOP AT THE RIM?

"Hazy" bright spots lie in a crater named Occator in the northern hemisphere of Ceres.
The crater is around 22 degrees North and at a higher elevation that most other craters.
Occator is 60 miles (90 km) across and 2 miles (4 km) deep. This image was generated
from July 2015 NASA animation using earlier images and Dawn spacecraft data from
2,700 miles altitude in which the vertical relief has been exaggerated by a factor
of 5 to better highlight topography and subtle features. Credits: NASA/JPL-Caltech/UCLA/MPS/DLR/IDA/LPI

OK, first of all, this is not a statement that is without controversy. And that statement about 'haze' was made definitely by a team member, but other team members are questioning it now. 'haze.' Some team members are saying this is scattered light — or equivalent to scattered light. Since it was such a faint observation, they had to blow up the images further than really was justified and perhaps made some artifacts in the data.

BUT PROFESSOR RUSSELL, THOSE PHOTOS FROM JULY OF THE BRIGHT SPOTS DO LOOK LIKE THERE IS A HAZE.

They certainly do look fuzzy. And there was what could be a cloud over the rim. To me it really looked like a cloud. But it wasn't my instrument; it was my spacecraft. At the present time, it's one of those things where we haven't come up with the definitive consensus yet.

IS IT POSSIBLE THAT THE DUSTY MATERIAL THAT YOU ARE NOW HYPOTHESIZING IS SOMEHOW SUSPENDED ABOVE THESE BRIGHT SPOTS IN THE AIR AND DEPENDING ON WHETHER LIGHT IS SHINING THROUGH IT OR NOT, IT WOULD LOOK CLOUDY, MISTY, OR LIKE A HAZE?

Yeah, that's what we thought. That would give us some evidence for some sort of atmosphere because there's got to be air at some density to hold up those little particles of salt or whatever.

But the counter-evidence is that we took some photos from the night side of the planet and looked back towards the Sun. And the estimates of how much atmosphere could be there from those photos suggest that there's not very much discernible atmosphere on the planet.

What the team verbally reported back to me is that once they were enthusiastic about this idea of the amount of forward scattering, but the amount of forward scattering was really very little, if any at all. And so, we haven't got evidence for an atmosphere at the present time.

SO THE MYSTERY IS EVEN GREATER THEN ABOUT THE BRIGHT SPOTS BECAUSE IF YOU DON'T HAVE AN ATMOSPHERE, AND IF YOU HAVE ELIMINATED NOW WITH SPECTROGRAPHIC DATA THAT THERE IS NOT H2O OVER THAT OCCATUR CRATER, THEN YOU'VE GOT SOMETHING THAT IS VERY WHITE, IS VERY BRIGHT, HAS BEEN SUSTAINING A REFLECTION THAT HUBBLE PICKED UP AND THAT DAWN HAS BEEN PHOTOGRAPHING OVER 11 YEARS.

THE ISSUE THEN WOULD BE WHAT KIND OF SUBSTANCE, WHAT ELEMENT—MAYBE SOMETHING WE DON'T EVEN KNOW ABOUT—IS COMING FROM BELOW GROUND AND HAS THE ABILITY TO COVER THE GROUND AND SUSPEND ITSELF ABOVE THE GROUND?

Well, anything that came out that had any reasonable amount of mass would fall back to the surface. So let's say that there's some liquid down there. It's got to be water down there somewhere. So you know, you tap through the surface somehow, maybe a meteorite strike, or maybe it just works its way through somehow, melts the ice above it and comes out and sprays the surface for a little while and then freezes and disappears. But that salty material that came out with the water, when the water went away, then the salt would fall to the surface as a little bit of snow. Even though it's the vacuum of space, it would fall back on a surface because there's nothing to blow it around.